Axiom Home Page Forums General Discussion Stereo Triggered pulled - Active LFR-1100's are on order!

Mojo ... I maybe wrong but I believe a CD stores it’s audio as 16 bit samples. There are a bit more than 44K of these numbers a second. I assume that these numbers come off the CD and are stored in a buffer to be reclocked to the D/A.

I imagine that today one would buffer many seconds of audio at a time and go back for more when needed making the transport just a skip free storage device.

Ok, on to jitter ...I doubt jitter on the D/A side of things would really matter that much given a reasonable clock and output filtering. That said, I’m sure you will educate me. Now when one is going the other way, the A/D side of things, jitter will raise your noise floor.

I'm not an expert so don't quote me on any of this. There are over 4 Mbits/sec retrieved from a CD. I think about 1.5 million of that is audio data and the rest is used for ensuring integrity in the modulation scheme.

You know those pits on the CD? It's the transition between the pits and the land that is read as ones and zeros - these are the zero crossings of the modulated analog signal. If the production process is bad and the transition between the pits and land isn't sharp, there's phase shift in the modulated signal and the zero crossings aren't where they should be. This is really bad for highs and those highs are responsible for soundstage width at least.

On jitter, I am an expert but not on audio. Rather, on sampling power system harmonics which are all in the audible frequency spectrum. So it's sort of the same thing as audio. Jitter affects D/A converter synchronization. I remember we had 100 picoseconds of jitter and it affected performance out to the 30th harmonic. I'm extrapolating here from my experience but I surmise low amplitude, high(er) frequency audio is affected. That screws with depth cues.

Craig how many vortex ports are on the back of the actives? The passives have two. The M100s have 5.

I will look tonight.

Thank you.

Note in the measurements below on Craig's new CD player, the jitter is five times less than the ITU-T standard for 20Hz to 100KHz. I am sure Craig factored this into his purchase decision.

We peasants will have to listen to our active LFRs via Spotify, PS3 and other jittery mechanisms.

http://i.nextmedia.com.au/Assets/yamaha_cd-s2100_cd_player_review_test.pdf

LFR1100s, 3 rear ports

Mojo, I think the discussion was about high end transports vs typical mid end.
A badly made disk is what it is ...

I think pcm encoding is an option but I’m not sure it’s used or used as you describe ... if it is then a d/a would not be needed ... and I’m not sure how the error correction would work then ...

Thank you.

You are welcome Mr. Mojo!
LFR1100 Actives. 3 ports